Caspae schumachee



C. SCHUMACHER.

RATGHBT DRILL. No. 297.171. Patented Apr. 22, 1884.

Mir E UNITED STATES PATENT Ormea.

GASPAR SOHUMACHER, OF KALK, GERMANY.

RATCHET-DRI LL.

SPECIFICATION forming part: of Letters Patent No. 297,171, dated April22, 1884.

Application tiled December 21, 18552.

To all whom it may concern,.-

Be it known that I, GASPAR SoHUMAoHnR, of Kalk, Germany, have invented anew and useful Improvement in Ratchet-Braces, (for which I have obtaineda patent in Germany, bearing date July 21, A. D. 1881, No. 17,4770 ofwhich the following is a specification.

My invention has for its object to construct a ratchet-brace providedwith automatic and variable feed.

In describing the invention, reference will be made to the annexeddrawings, in which Figure 1 is a cross-section, and Fig. 2 alongitudinal section, of an improved ratchet-brace.

The construction of the tool is as follows: A drill-holder, a, isprovided at one end with an opening, g, for the drill, and at the o therend with a screw-thread, in which the screw-spindle b may be turned bymeans of the lever b. Over the upper end of the drill-holder iitsanadjusting-sleeve, c, forming at the lower end a ratchet-wheel, c',facing the ratchet-wheel o', formed on the drill-holder a. the adjlisting-sleeve c is secured a feather or key, d, serving to attach thesleeve to the spindle b. The ratchet-wheel a has a tooth more than thewheel c', and both may be turned by a pawl, e, pivoted on a pin,f. Thepawl is pressed against the wheels by a spring, h. The whole mechanismis Mheld by a lever, k, provided with a. recess for the ratchet-wheels,ratchet, and spring, which recess is covered with a lid, Z, secured tothe lever by screws m m. Outside the lid there may be keyed on thesleeve c a third ratchet-wheel, a, having one or two teeth less than thewheel c. A pawl, o, gearing into the ratchet-wheel n, may be turnedaside and set out of action when desired.

The operation of the tool is as follows: The drill is held upon thepiece of work', and the screw-spindle is turned out of theadjustingsleeve until the pointed head of the spindle.

abuts against the counter-plate, which forms the necessary support indrilling. The lever k is then turned to and fro, whereby the drillholdera and the sleeve c are turned in the same direction, but throughdifferent lengths of travel, owing to the difference in the number ofteeth of the ratchet-wheels c and a.

After every forward motion of the lever k for To the inside of (Nomodel.) Patented in Germany July 21, 1851, No. 17,477.

two ratchet-wheels, the contact-faces of these two teeth being in onevertical plane, while the contact-faces of all other teeth of one wheelare intermediate between the contactfaces of the other wheel. Il", now,thelever k is turned back for several teeth, the pawl will slide overthe teeth of both wheels, and when the forward motion commences the pawlwill first come in gear with a tooth of the ratchetwheel having thesmaller pitch-that is to say, the upper wheel, c-and turn the same aloneuntil the pawl comes also in contact with the nearest tooth of the wheela', after which both wheels turn together until the end of the stroke ofthelever k. As thesleeve cis keyed on the spindle b, the latter turns inthe drillholder a as long as a. remains stationary-that is to say, aslong as the pawl is in contact with the upper wheel, c', only. By thismotion the spindle b will be screwed out of the drill- Iholder a, andthereby feed the latter forwarduntil `the pawl has come in contact withboth ratchet-wheels, after which only a rotary motion of the drill takesplace. The ratio between the rotary motion of the drill and its feedmotion will remain approximately constant as long as there is only oneratchetwheel (c) on the sleeve c. In order to render such feed motionvariable, a third ratchetwheel, n, is keyed on the sleeve c outside thelid; or several such ratchet-wheels may be keyed on. As the outerratchet-wheel has at least one tooth less than the wheel c', it willcommence to turn sooner and the feed motion will be greater.

In ratchet-braces, the combination of a drill-holder, a, provided withinternal screwthread, and with ratchet-teeth a', with a,

screw-spindle, b, and adjusting-sleeve c, secured to the screw-spindle,and having ratchetteeth c', spring-pawl e, hand-lever k, ratchetwh eela, secured to the adj usting-sleeve c', and having at least one toothless than the sleeve c, and a pawl, o, adapted to be put in and out ofgear with the wheel a, substantially as and for the purpose described. l

In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

C. SCHUMACHER. Vitn esses:

G. ADoLF HARTZ, u WILH. HARTMANN.

ICO

